Istrate Energietechnik GmbH

During the Major Inspection activities, especially if major repairs have been done (such as blades replacement, shaft machining, retaining rings replacement, etc.) low speed balancing of the Turbines or Generators are performed on transportable balancing machines. Although the low speed balancing is done at speeds bellow 300 rpm, a proper selection of the balancing method and balancing planes, together with the rotor deformation measurements and vibration history of the machine, will warrantee in most of the cases a low vibration during operation without the necessity of a trim balancing at the re-commissioning. Our experience with both soft bearing balancing machines and resonant balancing machines was proven to achieve a good vibration level after the low speed balancing when tested at high speed.